Japanese laid-open Patent Publication No. 2009-125000 (Patent Document 1) discloses animal litter which comprises a plurality of granules, each having an inorganic porous material, silica gel and a hydraulic inorganic binder for integrally binding them.
It is known that indoor animals, particularly cats have a habit of burying their own excrement in sand or pawing animal litter after excretion in a litter box (“sand pawing”).
In order to prevent the granules from easily scattering away from the litter box during the sand pawing, conventionally, in manufacturing animal litter, an inorganic porous material, silica gel and a hydraulic inorganic binder are mixed and granulated while water is added, and in this process, pressure is applied to the mixture dissolved in water until the binder is hardened. In this manner, granules having relatively high density can be formed, so that the animal litter can be provided in which the granules do not easily scatter away even by the sand pawing.
By thus continuing to apply strong pressure to the mixture dissolved in water during the time required for the binder to be hardened, the shape retentively of the granules can be secured. In such a case, the weight of the granules increases and accordingly the effect of preventing the granules from scattering away can be obtained. However, the density of the granules of the animal litter increases and thus the weight of the granules unnecessarily increases, which causes various problems such as the waste of materials and suppression of the cost reducing effect.
Patent Document 1: Japanese laid-open Patent Publication No. 2009-125000